The present invention relates to a protective cushion for protection of a vehicle occupant's head. More particularly, the present invention relates to a cushion which is folded and disposed along an upper corner of a side of a vehicle cabin in the normal state and is inflated into a curtain shape to expand over windows of side doors and a B-pillar in the event of a side impact collision or roll-over of the vehicle.
One embodiment of a protective cushion for protection of occupant's head, is a curtain airbag which is folded and disposed along an upper corner of a side of a vehicle cabin in the normal state (i.e., when a vehicle is not in the emergency situation such as the event of a vehicle collision). The airbag inflates into a curtain shape to expand over windows of side doors and a B-pillar in the event of a side impact collision or roll-over of a vehicle. The protective cushion may include two base fabrics which are joined together along their peripheries at a line-shaped joint by stitches of sewing yarns to form a chamber between the base fabrics. The chamber is designed to be filled with gas.
FIGS. 6(a)-6(c) disclose an exemplary protective cushion or side airbag for protection of a vehicle occupant's head. FIG. 6(a) is a front view of a protective cushion 1 for protection of vehicle occupant's head. FIG. 6(b) is a sectional view taken along a B—B line of FIG. 6(a), and FIG. 6(c) is a sectional view taken along a C—C line of FIG. 6(a).
As shown in FIG. 6(b), the protective cushion 1 includes a cabin-side (i.e. passenger side) base fabric 2 and a window-side base fabric 3 which are superposed and sewn to each other so as to form a chamber 4 between the base fabrics 2 and 3.
The base fabrics 2, 3 are joined to each other along a joint 10 extending around the peripheries of the fabrics. As shown in FIG. 6(a), the joint 10 may extend inward from the edge of the fabric. The curtain may also include joints 11, 12 for subdividing the chamber 4, and circular joints 13 for reinforcing areas around ends of the line-shaped joints 11, 12. Each of the circular joints 13 may include a circular opening 14 formed at the center thereof by cutting out the base fabrics 2, 3.
The cushion 1 extends along the side of the vehicle cabin in the longitudinal direction of the vehicle. The cushion 1 is provided at the front end and the rear end in the longitudinal direction thereof with projecting portions 16, 18 which are formed with holes 17, 19 to facilitate installation of the cushion to the vehicle body. The cushion 1 is provided along the upper edge thereof with a plurality of projections 20 which are also formed with holes 21 to facilitate connection of the cushion 1 to the vehicle body.
A gas inlet 5 through which gas from an inflator (not shown) is introduced is formed at the front end or the rear end (see FIG. 6(a)) of the cushion 1. It should be understood that the position of the gas inlet 5 is not limited thereto and the inflator may be disposed inside the cushion.
The line-shaped joint 11 is apart from the line-shaped joint 10 extending along the cushion. Each end of the line-shaped joint 11 are respectively connected to the circular joints 13.
The upper and lower ends of the line-shaped joint 12 both are apart from the line-shaped joint 10 extending along the upper edge and the lower edge of the cushion and both are connected to the circular joints 13, respectively. The line-shaped joints 11, 12 limit the thickness of the inflated chamber 4. The circular joints 13 reinforce the ends of the line-shaped joints 11, 12.
The cushion 1 may be installed so that the projecting portion 16 at the front end is fixed to an A-pillar of the vehicle by bolts or rivets through the holes 17 thereof. The projecting portion 18 at the rear end may be fixed to a C-pillar by a bolt or rivet through the hole 19 thereof, and the projections 20 along the upper edge may be fixed to a roof side rail by bolts or rivets through the holes 21 thereof. Prior to deployment, the cushion 1 is stored in a folded condition along the upper corner of the vehicle side surface along the roof side rail. The folded cushion 1 may be covered by a cover (not shown). The cover is adapted to be torn or opened when the cushion 1 is inflated.
When the vehicle suffers a side impact collision or roll-over, the inflator (not shown) is actuated, gas flows into the chamber 4 through the gas inlet 5 so that the cushion 1 is inflated and deployed downwardly along the side surface of the vehicle cabin into the curtain shape, thereby protecting the head of occupant.
It is preferable to maintain the head protecting cushion in the inflated state for a period of time (at least several seconds) after inflation not only for prevention of collision of the occupant's head to the window glass or the B-pillar at the instant of the side impact collision of the vehicle but also for protection of the occupant just after the roll-over of the vehicle.
When the protective cushion for protection of vehicle occupant's head is inflated over the window glasses, there is possibility that the cushion may be damaged by fragments of window glasses broken by a vehicle collision or roll-over thereby causing the inner pressure of the cushion to be reduced. Therefore, it is preferable that the protective cushion is provided with measures for coping with this.
Japanese Unexamined Patent Publication No. 11-310097 (incorporated by reference herein) discloses a cushion with dual structure comprising a protective cushion for protection of vehicle occupant's head and an outer cushion in which the protective cushion is accommodated.
As explained concretely, the cushion of the above publication includes a dual structure constituted of an outer cushion made of a woven fabric and an airtight inner cushion both having nearly the same shape when inflated. The outer cushion and the inner cushion are not bonded to each other.
However, since the outer cushion and the inner cushion are not bonded to each other at all, the outer cushion may not follow the movement of inflation of the inner cushion and may sometimes disturb the inflation of the inner cushion. Thus, there remains a need to provide a cushion for protecting a vehicle occupant's head that includes increased resistance to damage.